At Las Vegas Motor Speedway on Sunday, in a city of chance, he needed no help at all to win the Shelby American Nascar Sprint Cup race.

Johnson reeled in his Hendrick Motorsports teammate Jeff Gordon, who had dominated the race, to win for the second consecutive week. He took four tires on the final pit stop, chased Gordon for 17 laps, then finally sailed past his Hendrick Motorsports teammate with 17 laps to go to wrap up the win.

The victory was the 49th of Johnson’s career and his fourth at the Las Vegas track.

Gordon led 218 of the 267 laps while searching for his first victory in almost a year. He was out front when Kevin Conway’s spin brought out the final caution, and he debated his pitting strategy with his crew chief, Steve Letarte.

The call was made at the last second for Gordon to come in, and Letarte changed just two tires to get Gordon back on the track before his competition. Knaus called for four tires, a decision that put Johnson fourth for the restart.

Clint Bowyer, who did not pit, restarted as the leader with 34 laps to go. Gordon and Johnson immediately split him to move back to the front. Gordon held the top spot for 17 trips around the track, but he fretted several times as Johnson looked both inside and out.

“Not much we can do about those four tires,” Gordon told his crew. “We’ll give it everything we’ve got.”

Letarte replied: “I’m with you. Just do the best you can. Make it hard for him either way.”

Gordon tried to hold off Johnson, but Johnson scooted past with 17 laps to go. He quickly pulled away, and Gordon faded to third, unable to hold off Kevin Harvick, who finished second to Johnson for the second consecutive week.

“If we won the race, we’d look like geniuses — Steve would have,” Gordon said. “The fact that we lost the race, now Chad looks like a genius. I talked to Steve briefly after the race. He’s pretty upset, obviously. I think he just felt like more people were going to take two tires. Shoot, we were thinking for a split second to stay out.

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“I felt like we needed to come in and get some tires, but I felt like two tires was the right call, too.”

Harvick said his Richard Childress Racing team had nothing to prove to Johnson.

“We can run with them, and they know it,” he said.

The roles were reversed a week ago in California, when a timely caution put Johnson in the lead. He had Harvick chasing him over the final laps, and Harvick appeared poised to take the win until he brushed the wall late.

That victory frustrated some drivers who have grown tired of Johnson’s four-year reign as the Cup champion.

“When you’re a good team, like last week, people were talking about, ‘Man, look how lucky they are,’ ” Gordon said of Johnson. “That’s not luck. You do everything you can as a team right, and when everything is clicking, good things happen.”

But Gordon, for the first time maybe since his classic 2007 battle with Johnson for the championship, said he thought his team could keep pace with Johnson, his onetime protégé.

“I’m disappointed, but at the same time, you know, we haven’t dominated like this in a very, very long time,” he said. “I’m very really excited about this race team. I think we’ve got more of what we showed today that, that we’re going to show a lot more.”

Mark Martin finished fourth to give Hendrick three cars in the top 10. Matt Kenseth was fifth, followed by Joey Logano, Tony Stewart, Bowyer, Kasey Kahne and Greg Biffle.

A version of this article appears in print on March 1, 2010, on Page D11 of the New York edition with the headline: Tire Game: Johnson’s 4 Beat Gordon’s 2. Order Reprints|Today's Paper|Subscribe